Stability modeling methodologies to enable earlier patient access.

Over recent years, confidence has been gained that predictive stability modeling approaches using statistical tools, prior knowledge and industry experience enable, in many instances, a robust and reliable shelf-life/expiry or retest period prediction for medicinal products. These science and risk-based approaches can compensate for not having a complete real-time stability data set to be included in regulatory applications at the time of initial submission and, thereby, accelerate the availability of new medicines. Examples of predictive stability modeling include accelerated stability assessment procedure (ASAP), advanced kinetic modeling (AKM), and novel modeling approaches that involve the use of Bayesian statistics and Artificial Intelligence (AI) applications such as Machine Learning (ML), with applicability to both synthetic and biological molecules. For biologics, product-specific and platform prior knowledge could be used to overcome model limitations known for non-quantitative stability indicating attributes. A successful ongoing verification approach by comparing the predicted data with real-time stability data would be an appropriate risk management approach which is intended to address regulatory concerns, and further build confidence in the robustness of these predictive modelling approaches with regulatory agencies. Global regulatory acceptance of stability modeling could allow patients to receive potential life-saving medications faster without compromising quality, safety or efficacy.

Next-generation Dengue Vaccines: Leveraging Peptide-Based Immunogens and Advanced Nanoparticles as Delivery Platforms.

Dengue, caused by the dengue virus (DENV), is a prevalent arthropod-borne disease in humans and poses a significant burden on public health. Severe cases of dengue can be life-threatening. Although a licensed dengue vaccine is available, its efficacy varies across different virus serotypes and may exacerbate the disease in some seronegative recipients. Developing a safe and effective vaccine against all DENV serotypes remains challenging and requires continued research. Conventional approaches in dengue vaccine development, using live or attenuated microorganisms or parts of them often contain unnecessary epitopes, risking allergenic or autoimmune reactions. To address these challenges, innovative strategies such as peptide vaccines have been explored. Peptide vaccines offer a safer alternative by inducing specific immune responses with minimal immunogenic fragments. Chemical modification strategies of peptides have revolutionized their design, allowing for the incorporation of multi-epitope presentation, self-adjuvanting features, and self-assembling properties. These modifications enhance the antigenicity of the peptides, leading to improved vaccine efficacy. This review outlines advancements in peptide-based dengue vaccine development, leveraging nanoparticles as antigen-displaying platforms. Additionally, key immunological considerations for enhancing efficacy and safety against DENV infection have been addressed, providing insight into the next-generation of dengue vaccine development leveraging on peptide-nanoparticle technology.

A Quantitative Clinical Pharmacology-Based Framework For Model-Informed Vaccine Development.

Historically, vaccine development and dose optimization have followed mostly empirical approaches without clinical pharmacology and model-informed approaches playing a major role, in contrast to conventional drug development. This is attributed to the complex cascade of immunobiological mechanisms associated with vaccines and a lack of quantitative frameworks for extracting dose-exposure-efficacy-toxicity relationships. However, the Covid-19 pandemic highlighted the lack of sufficient immunogenicity due to suboptimal vaccine dosing regimens and the need for well-designed, model-informed clinical trials which enhance the probability of selection of optimal vaccine dosing regimens. In this perspective, we attempt to develop a quantitative clinical pharmacology-based approach that integrates vaccine dose-efficacy-toxicity across various stages of vaccine development into a unified framework that we term as model-informed vaccine dose-optimization and development (MIVD). We highlight scenarios where the adoption of MIVD approaches may have a strategic advantage compared to conventional practices for vaccines.

Monitoring the COVID-19 immunisation programme through a national immunisation Management system - England's experience.

BACKGROUND: In England routine vaccinations are recorded in either the patients General Practice record or in series of sub-national vaccine registers that are not interoperable. During the COVID-19 pandemic it was established that COVID vaccines would need to be delivered in multiple settings where current vaccine registers do not exist. We describe how a national vaccine register was created to collect data on COVID-19 vaccines. METHODS: The National Immunisation Management System (NIMS) was developed by a range of health and digital government agencies. Vaccinations delivered are entered on an application which is verified by individual National Health Service number in a centralised system. UKHSA receive a feed of this data to use for monitoring vaccine coverage, effectiveness, and safety. To validate the vaccination data, we compared vaccine records to self-reported vaccination dose, manufacturer, and vaccination date from the enhanced surveillance system from 11 February 2021 to 24 August 2021. RESULTS: With the Implementation of NIMS, we have been able to successfully record COVID-19 vaccinations delivered in multiple settings. Of 1,129 individuals, 97.8% were recorded in NIMS as unvaccinated compared to those who self-reported as unvaccinated. One hundred percent and 99.3% of individuals recorded in NIMS as having at least one dose and two doses of the COVID-19 vaccine were also self-reported as having at least one and two doses, respectively. Of the 100% reporting at least one dose, 98.3% self-reported the same vaccination date as NIMS. A total of 98.8% and 99.3% had the same manufacturer information for their first dose and second dose as that which was self-reported, respectively. DISCUSSION: Daily access to individual-level vaccine data from NIMS has allowed UKHSA to estimate vaccine coverage and provide some of the world's first vaccine effectiveness estimates rapidly and accurately.

Development of effective messages to promote maternal immunization in Kenya.

OBJECTIVES: This study evaluated messages and communication approaches for maternal immunization uptake in Kenya. We identified persuasive communication aspects that would inform maternal immunization attitudes, intent, and vaccine uptake. METHODS: We conducted a two-phased mixed methods study with pregnant women and their male partners in three regions of Kenya. Discussions were conducted in English and Swahili languages by trained focus group moderators. Baseline measures included a survey and discussions about potential messages and accompanying visuals. Follow-up focus groups with the same participants included a survey about previously discussed messages, visuals, and communication impressions. The second round of focus groups focused on message preferences developed from the first round, along with rank order discussion for final message selection. Following transcription of focus group discussions, we conducted analyses using NVivo software. Quantitative data analyses included frequencies, factor analyses, reliability assessment, regression modeling, and comparative assessment of rank order. RESULTS: The sample (N = 118) included pregnant women (n = 91) and their partners (n = 27) from diverse Kenyan regions (Bondo/Lwak/Siaya, Mombasa, and Nairobi). A four-factor solution resulted from factor analyses that included subscales "positive ad attitudes" (n = 5 items, α = 0.82), "negative ad attitudes" (n = 4 items, α = 0.75), "ad indifference" (n = 2 items, α = 0.52), and "ad motivation" (n = 4 items, α = 0.71). Overall, the positive ad attitudes factor (ß = 0.61, p = 0.03) was the only significant component in the overall model examining message selections (χ2(6) = 262.87, p = 0.17). Among the tested concepts, we found that source and situational cues had a strong influence on women's attitude formation and intention to obtain recommended maternal vaccinations. With self-acknowledged variations in knowledge, participants were particularly attuned to images of relatable women, providers, and depictions in realistic or actual Kenyan clinical settings. CONCLUSIONS: The results indicated that positive attitudes were shaped by incorporating highly relatable factors in messages. Implications for subsequent campaigns and research directions are discussed.

Atomic-Layer Deposition Processes Applied to Phage λ and a Phage-like Particle Platform Yield Thermostable, Single-Shot Vaccines.

Especially in developing countries, the impact of vaccines can be limited by logistical obstacles associated with multiple dose regimens, pathogen variants, and challenges imposed by requirements for maintaining vaccines at low temperatures during shipping and storage. Thus, there is a need for vaccines that can be flexibly modified to address evolving pathogen landscapes, are stable outside of narrow "cold-chain" temperatures and require administration of only single doses. Here we demonstrate in proof-of-concept studies a vaccine platform that addresses these impediments to more widespread use of vaccines. The platform relies on bacteriophage-derived phage-like-particles (PLPs) that utilize a "plug-and-play" antigen delivery system that allows for fast, easy alteration of antigens on the surface of the PLPs. Thermostability of PLP-based vaccines can be achieved by embedding the PLPs within glassy particles produced by spray drying, and nanoscopic aluminum oxide layers applied using atomic layer deposition (ALD) can serve to control release of antigen in vivo, yielding vaccine formulations that elicit strong immune responses after administration of single doses. Bacteriophage λ was stabilized by spray drying to form powders that were incubated at 37 °C for up to a year without loss of infectious activity. PLPs derived from bacteriophage λ were expressed and purified from E. coli cultures, and an in vitro conjugation strategy was used to decorate specific PLP surface sites with T4-lysozyme, a model vaccine antigen. The resulting T4-lysozyme:PLP complexes (Lys-PLPs) were embedded in glassy dry powders formed by spray drying and coated with nanometer-thick layers of alumina deposited by ALD in a fluidized bed reactor. Alumina-coated Lys-PLP vaccines were stable for a least a month at 50 °C, and single doses of the alumina-coated vaccines elicited immune responses that were indistinguishable from responses generated by conventional two-dose, prime-and-boost dosing regimens of alum-adjuvanted Lys-PLP vaccines.

Particles in Biopharmaceutical Formulations, Part 2: An Update on Analytical Techniques and Applications for Therapeutic Proteins, Viruses, Vaccines and Cells.

Particles in biopharmaceutical formulations remain a hot topic in drug product development. With new product classes emerging it is crucial to discriminate particulate active pharmaceutical ingredients from particulate impurities. Technical improvements, new analytical developments and emerging tools (e.g., machine learning tools) increase the amount of information generated for particles. For a proper interpretation and judgment of the generated data a thorough understanding of the measurement principle, suitable application fields and potential limitations and pitfalls is required. Our review provides a comprehensive overview of novel particle analysis techniques emerging in the last decade for particulate impurities in therapeutic protein formulations (protein-related, excipient-related and primary packaging material-related), as well as particulate biopharmaceutical formulations (virus particles, virus-like particles, lipid nanoparticles and cell-based medicinal products). In addition, we review the literature on applications, describe specific analytical approaches and illustrate advantages and drawbacks of currently available techniques for particulate biopharmaceutical formulations.

Racial/Ethnic Disparities in Maternal Vaccine Knowledge, Attitudes, and Intentions.

OBJECTIVES: Although disparities in maternal vaccine acceptance among racial/ethnic groups are well documented, the reasons for these disparities are unclear. The objective of this study was to describe differences in pregnant women's knowledge, attitudes, beliefs, intentions, and trust regarding maternal and infant vaccines by race/ethnicity. METHODS: We collected survey data from 1862 pregnant women from diverse prenatal care practices in Georgia and Colorado from June 2017 through July 2018. We performed multiple logistic regressions to determine differences in intentions, knowledge, attitudes, beliefs, and trust by race/ethnicity and calculated odds ratios (ORs) and 95% CIs. RESULTS: Compared with White women, Black and Hispanic women were less confident in vaccine safety and efficacy and less likely to perceive risk of acquiring vaccine-preventable diseases, report provaccine social norms, indicate having enough vaccine knowledge, and trust vaccine information from health care providers and public health authorities. Black women were the least confident in the safety of the maternal influenza vaccine (OR = 0.37; 95% CI, 0.27-0.49); maternal tetanus, diphtheria, and acellular pertussis vaccine (OR = 0.37; 95% CI, 0.27-0.52); and infant vaccines overall (OR = 0.40; 95% CI, 0.28-0.58), and were least likely to intend to receive both maternal vaccines (OR = 0.35; 95% CI, 0.27-0.47) or all infant vaccines on time (OR = 0.45; 95% CI, 0.34-0.61) as compared with White women. CONCLUSIONS: Understanding differences in behavioral constructs integral to vaccine decision making among women of different races/ethnicities can lead to tailored interventions to improve vaccine acceptance.

Physicochemical Characterization of Sabin Inactivated Poliovirus Vaccine for Process Development.

Upscaling the production capacity of inactivated poliovirus vaccines (IPV) is urgently needed to eradicate polio worldwide. For the development of a robust manufacturing process for IPV, the impact of stresses on the properties of the poliovirus during manufacturing needs to be carefully evaluated. In this study, the physicochemical properties of Sabin poliovirus after low pH exposure were analyzed by asymmetrical flow field-flow fractionation coupled to multi-angle laser light scattering (AF4-MALS), sedimentation velocity analytical ultracentrifugation (SV-AUC), transmission electron microscopy (TEM), dynamic light scattering (DLS) and surface plasmon resonance (SPR). Low pH stress caused structural changes and aggregation of inactivated poliovirus virions, whereas degraded virion particles would not revert to native virions even after neutralization. Importantly, a complete loss of the D-antigenicity of IPV by low pH stress, followed by neutralization, was observed in SPR. These results suggest that the exposure of poliovirus particle to low pH stress would induce irreversible denaturation and aggregation of virus particles and lead to the loss of D-antigenicity; thus, low pH stress during the manufacturing of poliovirus vaccine should be minimized. The analytical methods above can be efficiently utilized in the development of high-integrity manufacturing processes and high-quality vaccines.

Heat Transfer During Freeze-Drying Using a High-throughput vial System in view of Process Scale-up to Serum vials.

Specific devices that combine 96-well plates and high-throughput vials were recently proposed to improve the efficiency of formulation screening. Such devices make it possible to increase the number of formulations tested while reducing the amount of active ingredients needed. The geometry of the product container influences the heat and mass transfer during freeze-drying, impacting product temperature (T_{p}) and therefore affecting the final product quality. Our study aimed to develop a tool to identify the operating conditions resulting in the same Tp when using high-throughput vials inside well plates and serum vials. Heat transfer coefficients between the shelf and the high-throughput vials (KV) were measured using the gravimetric method at chamber pressures ranging from 4 to 65 Pa for a batch of 576 vials located at the center of the well plates. KV distributions were used to predict TP distributions during primary drying of a 5% sucrose solution. Tp values were in average 8 °C higher using high-throughput vials instead of serum vials at chamber pressures lower than 12 Pa. This study provides a graphical solution for the management of process scale-up and scale-down between both types of product containers depending on their respective KV and product resistance to mass transfer.

Key recent advances in TB vaccine development and understanding of protective immune responses against Mycobacterium tuberculosis.

Tuberculosis is the leading infectious disease killer globally due to a single pathogen. Despite wide deployment of standard drug regimens, modern diagnostics and a vaccine (bacille Calmette Guerin, BCG), the global tuberculosis epidemic is inadequately controlled. Novel, effective vaccine(s) are a crucial element of the World Health Organization End TB Strategy. TB vaccine research and development has recently been catalysed by several factors, including a revised strategy focused first on preventing pulmonary TB in adolescents and adults who are the main source of transmission, and encouraging evaluations of novel efficacy endpoints. Renewed enthusiasm for TB vaccine research has also been stimulated by recent preclinical and clinical advancements. These include new insights into underlying protective immune responses, including potential roles for 'trained' innate immunity and Th1/Th17 CD4+ (and CD8+) T cells. The field has been further reinvigorated by two positive proof of concept efficacy trials: one evaluating a potential new use of BCG in preventing high risk populations from sustained Mycobacterium tuberculosis infection and the second evaluating a novel, adjuvanted, recombinant protein vaccine candidate (M72/AS01E) for prevention of disease in adults already infected. Fourteen additional candidates are currently in various phases of clinical evaluation and multiple approaches to next generation vaccines are in discovery and preclinical development. The two positive efficacy trials and recent studies in nonhuman primates have enabled the first opportunities to discover candidate vaccine-induced correlates of protection, an effort being undertaken by a broad research consortium.

Process Characterization and Biophysical Analysis for a Yeast-Expressed Phlebotomus papatasi Salivary Protein (PpSP15) as a Leishmania Vaccine Candidate.

Cutaneous leishmaniasis is a neglected tropical disease caused by the parasite Leishmania and transmitted by sandflies. It has become a major health problem in many tropical and subtropical countries, especially in regions of conflict and political instability. Currently, there are only limited drug treatments and no available licensed vaccine; thus, the need for more therapeutic interventions remains urgent. Previously, a DNA vaccine encoding a 15 kDa sandfly (Phlebotomus papatasi) salivary protein (PpSP15) and recombinant nonpathogenic Leishmania tarentolae secreting PpSP15 have been shown to induce protective immunity against Leishmania major in mice, demonstrating that PpSP15 is a promising vaccine candidate. In this study, we developed a fermentation process in yeast with a yield of ~1g PpSP15/L and a scalable purification process consisting of only 2 chromatographic purification steps with high binding capacity for PpSP15, suggesting that PpSP15 can be produced economically. The biophysical/biochemical analysis of the purified PpSP15 indicated that the protein was of high purity (>97%) and conformationally stable between pH 4.4 and 9.0. More importantly, the recombinant protein had a defined structure similar to that of the related PdSP15 from Phlebotomus duboscqi, implying the suitability of the yeast expression system for producing a correctly folded PpSP15.

Development of a Pertactin-Coated Beads Approach for Screening of Functional Monoclonal Antibodies.

Vaccine manufacturers have recently focused on the development of in vitro potency assays to promote 3R's strategy to replace animal testing. To be able to develop an in vitro potency assay, the immunological characteristics of the monoclonal antibodies used in the assay should be well understood as these antibodies likely reflect the biological activity of a vaccine product. The PRN antigen is one of the immunogenic antigens included in many commercialized acellular pertussis vaccines. Development of an in vitro potency assay for PRN is challenging as the biological properties of PRN are not well understood. In addition, binding of Bordetella pertussis to human cells occurs through multiple bacterial molecules, which makes it very challenging to assess if antibodies contribute to prevention of bacterial adhesion. To overcome these challenges, the functionality of several in-house anti-PRN mAbs has been investigated through a novel approach using PRN-coated beads. We were able to consistently quantify the inhibition of PRN-mediated adhesion for each anti-PRN mAb. Application of the protein-coated beads model has not only enabled screening of functional anti-PRN mAbs but can also be expanded for screening of antibodies against other bacterial or viral antigens.

Algorithm-Based Liquid Formulation Development Including a DoE Concept Predicts Long-Term Viral Vector Stability.

Specifically tailored amino acid-based formulations were previously shown to have a high potential to avoid stress-mediated degradation of complex molecules such as monoclonal antibodies and viral vectors. By using adenovirus 5 (Ad5) as a model, we studied whether such formulations may also efficiently protect viral vectors in thermal stress experiments and during long-term liquid storage. Algorithm-based amino acid preselection using an excipient database and subsequent application of design of experiments (DoE) in combination with a 37°C challenging model enabled the prediction of long-term storage stability of Ad5. By statistical analysis of the Ad5 infectivity, amino acids with significant influence on Ad5 stability were detected after 2 and 3 weeks of liquid storage at 37°C. Ad5 formulations comprising positively selected amino acids did not reveal any loss of infectivity after 24 months in liquid storage at 5°C. By contrast, a 2 log reduction after 3 months and complete loss of infectivity after 18 months was observed with a standard viral vector formulation. By an optimization round, we designed a simple and well-balanced formulation avoiding MgCl2, previously considered essential in Ad5 formulations. This work demonstrates the efficacy of an algorithm-based development approach in the formulation development for viral vectors.

Quality by Design-Driven Process Development of Severe Fever With Thrombocytopenia Syndrome Vaccine.

Owing to the biological activity of the vaccine, the complicated production process, sterility, and uniformity of the product, the producing process of the vaccine is complicated and the product quality hard to control. In recent years, with the development of basic science such as cell biology, molecular biology, and metabolic engineering, bioprocess engineering research has developed rapidly. Therefore, U.S. Food and Drug Administration and European Medicines Agency conduct stringent control over the development of biomedical process engineering and product quality. This case study describes an example of Quality by Design-driven process development for manufacturing a human vaccine produced with Vero cells. Cell density in harvest fermentation broth and antigenic titer were chosen as 2 critical quality attributes. The study through 3 rounds design of experiment revealed that H2O2 and cell boost 4 had a significant effect on antigenic titer. Ethanolamine had significant improvement in the final concentration of cells. Through the Monte Carlo simulation, the design spaces and control space of process parameters were determined. A successful validation in a bioreactor was executed to verify the results of a spinner flask. Our investigation presents a successful case of Quality by Design principle, which encourages other researchers to combine the methodology into other biopharmaceutical manufacturing process.

Yeast-based vaccines: New perspective in vaccine development and application.

In presently licensed vaccines, killed or attenuated organisms act as a source of immunogens except for peptide-based vaccines. These conventional vaccines required a mass culture of associated or related organisms and long incubation periods. Special requirements during storage and transportation further adds to the cost of vaccine preparations. Availability of complete genome sequence, well-established genetic, inherent natural adjuvant and non-pathogenic nature of yeast species viz. Saccharomyces cerevisiae, Pichia pastoris makes them an ideal model system for the development of vaccines both for public health and for on-farm consumption. In this review, we compile the work in this emerging field during last two decades with major emphases on S. cerevisiae and P. pastoris which are routinely used worldwide for expression of heterologous proteins with therapeutic value against infectious diseases along with possible use in cancer therapy. We also pointed towards the developments in use of whole recombinant yeast, yeast surface display and virus-like particles as a novel strategy in the fight against infectious diseases and cancer along with other aspects including suitability of yeast in vaccines preparations, yeast cell wall component as an immune stimulator or modulator and present status of yeast-based vaccines in clinical trials.